Open
class/rootfly/data/anderson/john-Anderson_SC_JRM_45-48.rfy
Navigate to Tube 48, window 14 (or thereabouts -- the important thing seems to be that there are lots of roots). Now, if you navigate the Session number (by either clicking or using the slider), everything works smoothly until you reach near the empty sessions 34-37. In particular, if you are on Session 38 and click either 37 or 39, the system will take a considerable amount of time (~4 seconds) to change sessions. Or if you are on Session 33 and click on either 32 or 34, it will do the same thing. What is interesting is that Sessions 38 and 33 are immediately adjacent to this empty group of sessions. In zoomed out (3x3) mode, I get the same behavior, except that it also seems to slow down during the empty sessions 34-37.
Notice that if you select a different window (in which there are no roots, or at least few roots), then the problem does not appear. The slowdown seems to be caused by some combination of lots of roots and empty sessions.
I'm running version 1.8.36 on a 2 GHz P4 machine with 1 GB RAM.